Britney Spears is ''excited'' about her sister's engagement.

The 31-year-old singer is thrilled at the news her younger sister, Jamie Lynne Spears, is to marry her boyfriend of three years, Jamie Watson, and the newly-brunette beauty shared her congratulations on Twitter.

Britney posted: ''So excited and happy for my sister, congrats @jamielynnspears - love you. (sic)''

Jamie, 21, revealed her happy news on Sunday (03.03.13) by posting an Instagram photo of her dazzling diamond engagement.

Referring to her fiance's gesture, she wrote: ''He did good! (sic)''

This is the actress-and-singer's second engagement after she was previously set to walk the aisle with her on/off boyfriend of five years CASEY ALDRIDGE, the father of her four-year-old daughter Maddie, before they split up in February 2010.

Jamie's happy news comes shortly after her sister Britney - who has sons Sean Preston, seven, and Jayden James, six, from her marriage to KEVIN FEDERLINE - split from her fiance of 13 months Jason Trawick in January and she recently admitted she will ''always love'' the talent agent.

She said: ''Jason and I have decided to call off our engagement. I'll always adore him and we will remain great friends.''